A metal or alloy workpiece may be coated by applying paint via a conventional electrophoresis coating (E-coat) process. There are several problems that are associated with standard electrophoresis coating processes. One problem is that electrophoresis coating typically requires a large reservoir of liquid paint for dipping a part to be painted. The paint in the large reservoir is often expensive to change or replace, which limits technical improvements that can be made economically. Another problem is that electrophoresis coating is not generally applicable to painting engines or transmissions because the hydrostatic pressure on the paint tends to force it into the interior of the engine or transmission through any small openings (e.g., around engine or transmission shafts). Accordingly, there is a need for a flow-coat electrophoresis process, which does not dip any parts into a pool of liquid paint.
Conventional flow-coat, electrophoresis process have been troubled with several technical problems. A first problem is that as excess paint drains or drips from one or more surfaces of the workpiece, air may become trapped in the paint and it may foam. Accordingly, there is a need to reduce the foaming of the paint under such circumstances so that the excess paint may be reused to coat other workpieces with high quality finishes. A second problem is to attain adequate control over covering all of the surfaces with the paint to a desired degree of thickness. A third problem is to prevent the paint in its liquid state from entering the cavities, openings, or shafts of certain workpieces. A fourth problem is to provide sufficient electrical current flux density to attract the paint to the workpiece.